There is no way I got root aphids via pure perlite, I just don't believe it. For one thing, two of the bags used were two or three years old. For another, it makes no sense that they'd even be able to establish themselves to the point where they could be brought in via bagged perlite (a mined product that undergoes heating as part of the processing, IIRC). That's why I believe they're already present in the environment, and that we humans have simply created a scenario where they're able to gain in numbers to sufficiently impact all growing scenarios.
Rather like how our seas are becoming jellyfish seas now that we've killed off apex predators. Can you dig where I'm coming from?
I agree. These have been a battle for over 100 years
http://www.wineeducation.com/phyl.html
Quote from another paper I read here
Louis Pasteur also was recruited to study the diseases of the silkworm, although not until around 1865. Pasteur was able to isolate several different microorganisms from silkworms each of which caused diseases. These included bacteria and protozoa and he also described a disease that we now know to be caused by a small RNA virus, which of course he could not identify. Certainly one would suspect that the research Pasteur conducted on insect diseases aided in his efforts to understand vertebrate diseases.
He also suggested using the protozoan against the grape phylloxera and recommended searching for a fungus that could infect these insects and which, once obtained, should be sprayed in infested vineyards.
The first scientific field test of microbial control was conducted by a Russian, Krassilstschik, who used the fungus Metarhizium anisopliae (Metchnikoff) against the sugar beet curculio, Cleonus punctiventris Germar.
- 50-80% mortality in test plots.
- by 1891 a commercially produced product was available in France, another fungus, Beauveria sp.
- in the 1930's a bacterium, Bacillus thuringiensis, was tested and it became commercially available shortly thereafter.
Each category will be described in more detail:
(1). def'n and description.
(2). some examples of these organisms.
(3). what do you need to know to use successfully.
(4). some examples of introductions, case histories.
The Grape Phylloxera
- in 1863 grape phylloxera,Phylloxera vitifoliae, an insect native to North America, was discovered in Europe, both in England and in France.
Origin in Europe?
- possibly transported to England on ornamental Virginia creeper or possibly on infested American grapestocks which had been imported since1629.
- 1840's, American vines had been imported to France in an effort to combat powdery mildew--may have been the source of phylloxera.
- once the phylloxera was established and devastating native vines, the American vines continued to flourish - unfortunately the American grapes made poor wine -but perhaps pointed to a solution.
- 1873, Riley (Missouri state entomologist) arranged for the shipment of a predatory mite, Tyroglyphus phylloxera, to France - became established - minimal effect.
- on U.S. vines phylloxera has a complex life cycle (has 19 different forms); root and leaf feeding forms; can produce galls both above and below the ground; sexual and asexual reproduction both occur.
- on European vines the infestation is restricted to the root and only parthenogenesis is observed--population dynamics?
- on the U.S. plants galls and other deformities slow growth - increase in root diameter one response of resistant plants - insects tend to stay on the same plant for considerable period of time.
- on European plants the infestation kills the root; phylloxera abandon the deteriorating plant to attack and kill a new plant - increases spread and losses.
- in France a reward of 320,000 francs was offered to anyone who could solve the problem.
solution: initially grafted European vines onto eastern U.S. root stock -- nobody collected the reward.
- Europeans grafted various plants and tested a variety of rootstocks including (AxR #1), not particularily resistant to phylloxera and rejected for widespread use.
comment on current problem in U.S.
- phylloxera not native west of of the Rockies.
- the grape stocks (in California) were not native to U.S. but came from Europe via Mexico with padres of Roman Catholic Church -1524.
- native grapes grew abundantly east of the Rockies and had evolved under constant association with phylloxera.
- when wine industry expanded rapidly in California, a rootstock was selected for its growth characteristics in this location - without due consideration for phylloxera!!!! ---- selected AxR #1.
- eventually phylloxera introduced.
- results - guess.
- requires the replacement of all the rootstock in Napa and Sonoma counties at an estimated cost of 1 billion dollars.
- several excuses have been made including:
i. people planted the wrong rootstocks - dishonest nurseries.
ii. a new phylloxera biotype, "B" now widespread and has adapted to AxR rootstock.
- French had stopped recommending AxR by the end of WWI; also discount biotypes because phylloxera adapts to feed on all rootstocks, a question of plant resistance.
- during this period one of the earliest chemical pesticides was developed; a mixture of lime and sulphur (Bordeaux mixture) had traditionally applied to grape vines that were accessible to the casual passerby with the intent of discouraging theft of grapes--apparently the insecticidal and antifungal properties of this mixture were observed--this led to the development of a mixture of copper sulphate and arsenic (Paris Green - Colorado Potato Beetle).
Lessons learned from grape phylloxera and other pest species.
- by late 1800's many entomologists were aware that a large proportion of the insect pests in any region were imported and the plea went forth in Canada for:
i. strict quarantine measures.
ii. importation for beneficial insects.
